Exhaust silencer for internalcombustion engines



Jane 16, 1945.

EXHAUST SILENCERS FOR INTERNAL-COMBUSTION ENGINES B. SMITH Filed Sept. 11, 1942 Patented Jan. 16, 1945 EXHAUST SILENCER FOR INTERNAL- COMBUSTION ENGINES Bernard Smith, Leeds, England Application September 11, 1942, Serial No. 458.020

' In Great Britain September 30, 1941 2 Claims.

This invention relates to exhaust silencers for internal combustion engines, the chief object being the provision of a new or improved exhaust silencer of simple and efficient construction whereby back pressure and noise will be reduced to a minimum as a result of the splitting up and rapid expansion and cooling of the exhaust gases.

According to the invention, the exhaust silencer comprises a pipe provided externally with a plurality of longitudinally disposed and circumferentially spaced expansion chambers which are placed in direct communication with the said pipe toward or near its inlet end and also toward v or near its outlet end by lateral ports, and means in the pipe, at an appropriate position between the two sets of lateral ports, for restricting the gas flow through the pipe and preferably splitting it up.

In order that the invention may be clearly understood and readily carried into efiect, the same will now be more fully described with reference to and by the aid of the accompanying sheet of drawings, wherein:

Figure 1 is a plan view of the exhaust silencer. Figure 2 is also a plan seen at a slightly difierent angle and with a portion broken away.

Figure 3 is an end view of Figure 1 drawn to a larger scale.

Figure 4 is a sectional end view of Figure 2 on line a-b also to a larger scale. Figure 5 shows end and sectional viewsof a detail hereinafter referred Referring now to the drawing, I represents the longitudinally disposed expansion chambers secured directly to the pipe 2, say by longitudinal welds at 3, so as to project radially therefrom and serve not only as expansion and cooling chambers for the gases which flow into and through them, but also as means for conducting and dissipating heat from the 'pipe 2, whilst the longitudinal spaces 4 afforded between the expansion chambers permit heat radiation. The expansion chambers l are of uniform angular cross-section constituted by a plurality of individual chambers secured to and placed around the exhaust pipe 2 so that cooling streams of air pass along all sides of each expansion chamber l. The ends of the expansion chambers are preferably inclined at 5 or otherwis directed toward the adjacent lateral ports 6 in the pipe 2 and are also preferably so disposed in relation thereto as not to afford a trap for any water of condensation, as it has been found that any water of condensation is blown up the inclined ends It at the outlet end of the expansion chambers I, through the adjacent lateral ports 6 and out through the pipe 2, while there may be a plurality of such sized ports.

lateral ports 6 which place each expansion cham. her in direct communication with the pipe 2at each end.

The means for restricting and splitting up the gas now through the pipe 2 may comprise a perforated disc 1, preferably having a plurality of orifices 8, which is located in the pipe 2 at a position preferably immediately in front of the lateral ports in the rear end of the pipe, and said disc 1 may be carried by the forward end of a tube 9 which is a sliding fit in the rear end of said pipe and is formed with radial ports III to register with the lateral ports 6 in the rear end of said pipe 2. In this connection this inner tube 9 may be longitudinally adjusted in the pipe 2 to bring its radial ports Ill more or less into reg- 'ister with the lateralports in the outlet end of the pipe2 so as to control the effective area of the outlets from the expansion chambers i into the pipe 2; or this control may be obtained by interchangeable inner tubes having differently perforated restriction member I in the pipe 2, the flow of gases from the engineexhaust into the inlet end of the pipe 2 will be apportioned as between the pipe 2 and the annular series-of expansion chambers I that portion of the flow which is passed by such restriction being split up into streams, and that those portions passing through the expansion chambers will, after cooling, re-enter the pipe 2 at or near the outlet end so as to re-unite with the flow through the pipe 2 and issue therefrom.

I claim: I

1. An exhaust silencer comprising a pipe having an inlet and-an outlet, separate external expansion chambers of angular cross section, said chambers extending outwardly from the pipe and spaced circumferentially thereof, all sides of the expansion chambers being in direct contact with the atmosphere and having open air flow passages between each expansion chamber, and the exhaust pipe having ports leading to said expansion chamber.

2. An exhaust silencer comprising a pipe havlng an inlet and outlet, separate external expansion chambers of angular cross section, inclined end closures for said expansion chambers, said chambers extending outwardly from the pipe and spaced circumferentially thereof, all sides of the expansion chambers being in direct contact with the atmosphere and having open air flow passages between each expansion chamber, and the exhaust pipe having ports leading to said expansion chamber.

BERNARD SMITH.

It will be seen that'by placing a 

